LAUSR

Ambient air pollution, namely exposure to air particulate matter (PM), has been shown to be connected with a number of adverse health effects. At least part of the effects can be caused by organic pollutant mixtures associated with PM, which can elicit a wide range of specific toxic potentials. These potentials could be affected by seasonal variation of pollutant mixtures and PM size fraction. To examine this, six size subfractions of PM10 were collected at rural and urban site in the Czech Republic in a year-long sampling campaign. The samples were assessed for aryl hydrocarbon (AhR)-mediated activity, estrogenicity and anti-androgenicity using mammalian cell models. The concentrations of detected toxic potentials differed among seasons. The greatest levels were observed in samples collected during winter when AhR-mediated effects and estrogenicity were at least 10-times greater than in summer. While the observed potentials were mostly less pronounced in samples from rural area, during winter, their AhR-mediated activity was twice as great as at the urban site. This was probably caused by the low-quality of fuel used for heating at the rural site. Assessed toxic potentials were associated mainly with PM size fractions with lesser aerodynamic diameters (<1 μm). Toxic potentials were compared with data from chemical analyses covering 102 chemicals from different pollutant groups to model their contribution to the observed effects. For AhR-mediated activity, chemical analyses explained on average 44% of the effect and the main identified effect-drivers were polycyclic aromatic hydrocarbons. For estrogenicity and anti-androgenicity, detected chemicals were able to explain on average less than 1.6% and 11% of the potentials, with their highest explicability reaching 13% and 57%, respectively. This was affected by the lack of data on specific toxic potency of some detected air pollutants, but also indicates a possible role of further not analyzed chemicals in these effects.